Reland; WebWaitableEvent: remove deprecated API to construct with no arguments
Reland; WebWaitableEvent: remove deprecated API to construct with no arguments

Changes from the first attempt:
 - leave "virtual" with TODO so that it does not cause build breakage on clang.

Original description:
Remove deprecated blink API to construct WebWaitableEvent
with no arguments, and replace it with a function to create
with ResetPolicy::Auto and InitialState::NonSignaled.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=198617

BUG=507224
TEST=gn build with is_clang=true

Review URL: https://codereview.chromium.org/1226163003

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@198645 bbb929c8-8fbe-4397-9dbb-9b2b20218538

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk